Walker A M, Lanes S F
Epidemiology Resources Inc., Chestnut Hill, MA 02167.
Stat Med. 1991 Aug;10(8):1181-96. doi: 10.1002/sim.4780100803.
In the context of reported data on asthma mortality, we examine two types of covariate misclassification. The first type is non-differential misclassification, in which the proportion of subjects misclassified is invariant over exposure and disease status. Building on work by Cox and Elwood and by Blettner and Wahrendorf, we find that the range of admissible values for misclassification proportions is bounded by the observed data, and may not include any values that account for observed heterogeneity of effect estimates. The second type is differential misclassification, in which the classification error differs according to the disease or exposure classes to which study subjects belong. If the relation between exposure and the confounding variable or between the confounding variable and disease is strong, differential misclassification can produce large variations in the stratum-specific odds ratio estimates.
在已报告的哮喘死亡率数据背景下，我们研究了两种类型的协变量错误分类。第一种类型是非差异性错误分类，即被错误分类的受试者比例在暴露和疾病状态上是不变的。基于考克斯和埃尔伍德以及布莱特纳和瓦尔伦多夫的研究成果，我们发现错误分类比例的可接受值范围受到观测数据的限制，并且可能不包括任何能够解释效应估计值观测异质性的数值。第二种类型是差异性错误分类，即分类错误根据研究对象所属的疾病或暴露类别而有所不同。如果暴露与混杂变量之间或混杂变量与疾病之间的关系很强，差异性错误分类会导致各层特异性比值比估计值出现很大差异。
